Mineral wool element with enhanced reaction to fire air duct comprising same

ABSTRACT

Element essentially consisting of mineral wool which exhibits an enhanced reaction to fire. Such an element is especially in the form of a panel and is used for the construction of air ducts. The panels comprise a glass wool core, said core being formed from glass fibers which act as components of the wool. The glass fibers of the element according to the invention have a diameter substantially greater than the diameter of the glass fibers which are presently used for the manufacture of panels or of ducts for similar applications. The glass fibers used according to the invention have a fineness index with a value which fluctuates between 5.8±0.5 for 6 grams. The invention also relates to a process for manufacturing an air duct from said panels.

[0001] The present specification refers to a patent application relatingto an element essentially consisting of mineral wool which exhibits anenhanced reaction to fire. Such an element is especially in the form ofa panel and is used for the construction of air ducts. The panelscomprise a glass wool core, said core being formed from glass fiberswhich act as components of the wool. The glass fibers of the elementaccording to the invention have a diameter substantially greater thanthe diameter of the glass fibers which are presently used for themanufacture of panels or of ducts for similar applications. The glassfibers used according to the invention have a fineness index with avalue which fluctuates between 5.8±0.5 for 6 grams. The invention alsorelates to a process for manufacturing an air duct from said panels.

[0002] The invention applies to the industry specializing in themanufacture and the conversion of glass as well as mineral wool andsimilar products. It is particularly aimed at uses in theair-conditioning field in which air ducts, especially ducts comprisingthermal insulation means, are widely used.

[0003] The applicant is aware of the current use, for manufacturing airducts, of elements consisting essentially of glass fibers whichconstitute a mineral wool, the fibers of which have a fineness indexlying between 4±0.4 for 5 grams. To obtain a quality product from suchfibers it is necessary to apply a finish of more than 10% by weight.Such an element leads to a poor reaction-to-fire classification of theair ducts which comprise it. The expression “fineness index” isunderstood to mean the value obtained by measuring the head loss of agas flowing through a specimen consisting of fibers to be characterized.This measurement gives an indication about the average diameter of thefibers and is usually known as the “micronaire measurement”. Thismeasurement is described in the ASTM D1448 standard (and in DIN 53941).This measurement was initially developed to characterize cotton fibersand has for a long time been used in the mineral fiber industry tocharacterize glass fibers. The “fineness index” is defined by thereading on the micronaire instrument for a given mass of product.

[0004] In the case of the fibers used according to the invention, itshould be understood that a micronaire reading of 5.8±0.5 is measuredwhen the quantity of fibers corresponding to a mass of 6 grams isintroduced into the measurement cell of the micronaire instrument.

[0005] To give an order of magnitude, it may be stated that a finenessindex of 4±0.4 for 5 grams corresponds to the characterization of glassfibers with a mean diameter of about 3.5 to 4 μm, a fineness index of5±0.5 for 6 grams corresponds to the characterization of glass fiberswhose mean diameter is about 9 μm and a fineness index of 6±0.5 for 6grams corresponds to the characterization of glass fibers whose meandiameter is about 12 μm.

[0006] To meet the reaction-to-fire standards in force, it would bedesirable to substantially reduce the content of finish which isincorporated into the mineral wool, that is to say the material whichcreates adhesion between the fibers. Tests have shown that finishcontents within a range lying between 5% and 6% (of the total mass ofthe fibrous product including the finish) make it possible to meet thestandards in force. However, it is not possible to use such finishcontents with the fibers known for such applications since it wouldresult in an unacceptable reduction in the quality of the product.

[0007] The applicant is therefore unaware of the existence at thepresent time of mineral wool ducts containing glass fibers which meetthe reaction-to-fire standards in force.

[0008] The element essentially consisting of glass wool with enhancedreaction to fire proposed by the invention is novel per se by having,within the context of its application, glass fibers, especially of thetype based on silicon, sodium, boron and calcium, with a diametersubstantially greater than that used in the fibers used at the presenttime. Surprisingly, it has been found experimentally that glass fibers,most particularly those which have a fineness index lying between5.8±0.5 for 6 grams, make it possible to obtain elements intended to beformed into panels which exhibit good usage properties, even when thefinish content is greatly reduced, especially when between 5 and 6% offinish is used. It then becomes possible to obtain a glass-wool-basedelement capable of having an improved reaction to fire and of meetingthe standards in force. Panels for the manufacture of air ducts may beformed from such an element.

[0009] The structure of these panels is especially of the type of panelsknown by the brand name CLIMAVER or CLIMAVER PLUS (sold for example byIsover). Rigid panels, such as those described in patent application FR2 786 550, may for example be manufactured from elements according tothe invention.

[0010] Specifically, a mineral fiber duct with enhanced reaction to fireis made from a panel intended for the construction of air ducts, saidpanel consisting of a glass wool core which has a glass fiber diametersubstantially greater than that of the products employed at the presenttime, defined by a fineness index which fluctuates between 5.8±0.5 for 6grams and in which the amount of finish incorporated into these fiberslies within the 5% to 6% range. According to a preferred embodiment, thefinish is a binder obtained from a phenol-formaldehyde resin.

[0011] The mineral wool duct with enhanced reaction to fire suggestedconsists of a panel for the manufacture of air ducts composed of a glasswool core having a fineness index which fluctuates in 5.8±0.5 for 6grams and a finish, especially adhesive, content of between 5% and 6%.

[0012] Preferably, the finish is a binder obtained from aphenol-formaldehyde resin.

[0013] To produce such a mineral wool duct, it is especially possible touse sections such as those described in patent application EP 0 791 791.

[0014] The invention also relates to a process for manufacturing an airduct, especially a heating and/or air-conditioning duct; said processincludes a step in which the panels defined above are assembled.

1. An element essentially consisting of mineral wool intended formanufacturing panels for the construction of air ducts, said elementbeing composed of a mineral wool core to which an adhesive is added,characterized in that the mineral wool fibers are glass fibers,especially of the type based on silicon, sodium, boron and calcium,which have a fineness index which fluctuates between 5.8±0.5 for 6 gramsand in that an adhesive is added to them in an amount which fluctuatesbetween 5% and 6%.
 2. The element as claimed in claim 1, characterizedin that the adhesive is a binder obtained from a phenol-formaldehyderesin.
 3. A panel made of mineral wool, characterized in that themineral wool is a glass fiber wool, especially of the type based onsilicon, sodium, boron and calcium, said glass fibers having a finenessindex of between 5.8±0.5 for 6 grams and said wool includes an adhesive,the content of which is between 5% and 6%.
 4. The panel as claimed inclaim 3, characterized in that the adhesive is a binder obtained from aphenol-formaldehyde resin.
 5. An air duct, especially anair-conditioning and/or heating duct, comprising panels made of glasswool according to either of claims 3 and
 4. 6. A process formanufacturing an air duct, especially an air-conditioning and/or heatingduct, characterized in that it includes a step in which the panelsaccording to either of claims 3 and 4 are assembled.